Rational design of hollow flower-like MoS 2 /Mo 2 C heterostructures in N-doped carbon substrate for synergistically accelerating adsorption-electrocatalysis of polysulfides in lithium sulfur batteries.

Lithium-sulfur (Li-S) batteries have been garnered significant attention in the energy storage field due to their high theoretical specific capacity and low cost. However, Li-S batteries suffer from issues like the shuttle effect, poor conductivity, and sluggish chemical reaction kinetics, which hinder their practical development. Herein, a novel hollow flower-like architecture composed of MoS 2 /Mo 2 C heterostructures in N-doped carbon substrate (H-Mo 2 S/Mo 2 C/NC NFs), which were well designed and prepared through a calcination-vulcanization method, were used as high-efficiency catalyst to propel polysulfide redox kinetics. Ex situ electrochemical impedance spectroscopy verify that the abundant heterojunctions could facilitate electron and ion transfer, revealed the excellent interface solid-liquid-solid conversion reaction. The adsorption test of Li 2 S 6 showed that Mo 2 S and Mo 2 C formed heterostructure generate the binding of polysulfide could be enhanced. And cyclic voltammetry test indicate boost the polysulfide redox reaction kinetics and ion transfer of H-Mo 2 S/Mo 2 C/NC/S NFs cathode. Benefiting from the state-of-the-art design, the H-Mo 2 S/Mo 2 C/NC/S NFs cathode demonstrates remarkable rate performance with a specific capacity of 1351.9 mAh g -1 at 0.2 C, when the current density was elevated to 2 C and subsequently reverted to 0.2 C, the H-Mo 2 S/Mo 2 C/NC/S NFs cathode retained a capacity of 1150.4 mAh g -1 , and it maintains exceptional long cycling stability (840 mA h g -1 at 2 C after 500 cycles) a low capacity decay of 0.0073% per cycle. This work presents an effective approach to rapidly fabricating multifunctional heterostructures as an effective sulfur host in improving the polysulfide redox kinetics for lithium sulfur batteries.